Magnetic resonance imaging apparatus and method wherein streak artifacts are minimized in modular k-space scanning
AssigneeSiemens Aktiengesellschaft
InventorsWolfgang Härer, Peter Speier
Life of this patent
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Abstract
In a method and MRI apparatus for the minimization of streak artifacts in modular k-space scanning in magnetic resonance imaging, an odd integer k-space scanning module number Nφ=2n+1 is defined that defines the number of incrementally rotated repeated modules of the k-space scanning process, a slice selection gradient selects any slice in the range of the object to be examined, and data for all Nφ angle-oriented k-space scanning modules in the selected slice acquired such that each k-space scanning module has an azmuthal distance of Δ φ 2 = 360 ° 2 N φ from both adjacent projections, with the direction of the scanning of the adjacent k-space scanning modules alternating.
Claims9
A method for minimizing streak artifacts in modular k-space scanning in magnetic resonance imaging, comprising the steps of:
- defining an odd integer k-space scanning module number Nφ=2n+1 that defines a number of incrementally rotated, repeated modules for scanning k-space;
- selecting, with a slice selection gradient, a slice in a volume of an object to be examined;
- acquiring data for all Nφ angle dependent k-space scanning modules in the selected slice so that each k-space scanning module has an azimuthal distance of
- Δφ/2=360 degrees/2Nφ from both projections adjacent thereto, by scanning each of said scanning modules in a vectorally unidirectional assigned scanning direction
- and alternating the vectorally unidirectional assigned scanning direction of adjacent k-space scanning modules;
- and
- reconstructing an image from the acquired data with streak artifacts minimized therein.
A magnetic resonance imaging apparatus comprising:
- a magnetic resonance scanner configured to receive an examination subject therein in order to obtain magnetic resonance signals, representing raw data, from the subject by executing an imaging sequence comprised of radio-frequency pulses and gradient pulses;
- and
- a computer configuration that operates said scanner and that is configured for entering said raw data as data entries in k-space, and configured for scanning k-space by defining an odd integer k-space scanning module number Nφ=2n+1 that defines a number of incrementally rotated, repeated modules in a k-space scanning procedure, and for activating at least one radio-frequency pulse and a slice selection gradient that selects a slice of the examination subject from which said raw data are to be acquired, and configured for operating said scanner in order to acquire said raw data for all Nφ angle-oriented k-space scanning modules in the selected slice by defining an azimuthal distance, of each k-space scanning module, of Δφ/2 =360 degrees/2Nφ from both adjacent projections, by scanning each of said scanning modules in a vectorally unidirectional assigned scanning direction, while alternating the vectorally unidirectional assigned scanning direction of adjacent k-space scanning modules, and configured to reconstruct an image from the acquired data with streak artifacts minimized therein.
A computer-readable medium encoded with a data structure and loadable into a control computer of a magnetic resonance apparatus for minimizing streak artifacts in modular k-space scanning, said data structure causing said computer to:
- define an odd integer k-space scanning module number Nφ=2n+1 that defines a number of incrementally rotated, repeated modules for scanning k-space;
- select, with a slice selection gradient, a slice in a volume of an object to be examined;
- acquire data for all Nφ angle-dependent k-space scanning modules in the selected slice so that each k-space scanning module has an azimuthal distance of Δφ/2=360 degrees/2Nφ from both projections adjacent thereto, by scanning each of said scanning modules in a vectorally unidirectional assigned scanning direction, while alternating the vectorally unidirectional assigned scanning direction of adjacent k-space scanning modules;
- and
- reconstruct an image from the acquired data with streak artifacts minimized therein.
Dependencies are inferred from the claim text.